The contact angle has to be provided for angular contact bearings, four-point ball bearings, spherical ball bearings, taper roller bearings ad spherical roller bearings. For taper roller bearings, the cup angle is used since this is the direction of the force. Using the 
-button, the direction of contact angle can be selected.
For double row angular contact bearings, the back-to-back arrangement has the larger width between the centers of pressure and it is also called O-configuration, while the face-to-face arrangement is the same as the X-configuration.
For three point bearings this input is used for the shim angle of the split ring. The 
-button allows to calculate the shim angle by given shim width. The resulting contact angle for axial contact is available as free contact angle in the results.
